Explosive hack increases AOE damage on shots. It does decent damage versus organics. I mean nothing extraordinary but it can kill a husk by itself on Gold. I can't remember on Platinum.
Are you saying explosive hack inc. weapon damage?
Yes, sabotage does decent damage vs. lower tier organics but the shadow can shoot and quickly break cloak with ES. And from my experience, ES does better damage than sabotage and has better AOE. That'll finish off anything that survives.
Also, when Alquinn was doing his HFI sub-16 solo, he reported that HFI with 27.5 % WD can OSK a gold phantom with a cloaked headshot where as a SI couldn't because of 5% less WD. I am not sure if he used PM or not. Vs. phantoms, one can make a similar argument.
From my experience, sniping shadow proved more effective than QFI.